“Our goal is to mimic natural biological machines by creating synthetic machines we can control,” said Hla, a professor of physics and astronomy.

Hla’s team observed up to 500 molecular motors move simultaneously in the same direction when the scientists applied 1 volt of energy through the tip of a scanning tunneling microscope. At lower levels of energy, the motors also rotated, but in different directions. However, this motion was not random, but showed patterns of coordination, Hla said.

In the experiment, scientists observed the synchronized movements at minus 316 degrees Fahrenheit.

The motors have two decks: The upper deck is the rotor and the lower deck is the stator, which has eight sulfur atoms that act as atomic glue to stick to surfaces of gold or copper. The rotating and stationary decks are connected with an atom of europium that serves as an atomic ball bearing.

Scientists at CEMES/CNRS in France synthesized the molecular motors, which include a dipole in the rotor arms, which means that they have a positive and negative side. This unique feature allows the individual motors to communicate and coordinate their motions, Hla’s team found.

In addition, the scientists learned that a hexagon arrangement of the motors is key for the synchronization, as it allows the motors to effectively communicate.

The molecular motors create a ferroelectric system, which is a prized property of materials used in various electronic devices, Hla added.

The nanomotors are so small that scientists can fit 44,000 billion of them in a 1 centimeter square area.

“One of the goals of nanotechnology is to assemble billions of nanomachines packed into a tiny area that can be operated in a synchronized manner to transport information or to coherently transfer energy to multiple destinations within nanometer range,” Hla explained.

The Ohio team received funding from the U.S. Department of Energy and the French team is supported by the French National Research Agency.

Ohio University team members on the study were S.-W. Hla, Y. Zhang, H. Kersell, V. Iancu, U.G.E. Perera, Y. Li, A. Deshpande and K.-F. Braun of the Department of Physics and Astronomy and Nanoscale and Quantum Phenomena Institute. Hla also is the head of the Quantum and Energy Materials research group at the Center for Nanoscale Materials in Argonne National Laboratory. C. Joachim, R. Stefak and J. Echeverria of CEMES/CNRS in France and G. Rapenne of CEMES/CNRS and the University of Toulouse in France collaborated on the study.

Note to media: High-resolution versions of the above images can be downloaded
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Image credit: Saw-Wai Hla.